“Some people will disagree, but for me if I’ve written a meaty, delightful, wonderful bunch of scenes and now I have to do the hard, connective, dog’s body work of writing, when I finish the dog’s body work, I’ll have a screenplay that I already love. I used to write chronologically when I started, from beginning to end. Eventually I went, That’s absurd; my heart is in this one scene, therefore I must follow it. Obviously, if you know you have a bunch of stuff to do, I have to lay out this, all this dull stuff, and I feel very uncreative but the clock is ticking. Then you do that and you choose to do that. But I always believe in just have as much fun as you can so that when you’re in the part that you hate there’s a light at the end of the tunnel, that you’re close to finished.”

Both approaches have merit. If you have tasks that stress you out just thinking about them, eat the frog in the morning to get it out of the way. Otherwise, leaving those tasks for last could make you get through them more quickly (especially when you're on a deadline).

Whedon is also a fan of David Allen's Getting Things Done. Though he hasn't finished the book, he offers a lot of great advice on juggling multiple projects and more in the link below.